1. Field of the Invention
The invention relates generally to processing of messages in a telecommunications network. In particular, the invention relates to processing a message in response to the type of upper layer protocol used in the message.
2. Background of the Invention
Packet data services are currently being developed for incorporation into existing cellular networks. For instance, Cellular Digital Packet Data (CDPD) and General Packet Radio Service (GPRS) are data services being integrated into existing cellular networks. CDPD is being integrated into Advanced Mobile Phone Service (AMPS) and TIA/EIA 136 and GPRS are being integrated into TIA/EIA 136. Once a packet data service is integrated into an existing cellular network, mobile stations are often able to receive service from both the packet data network and the existing cellular network. Although these mobile stations can receive multiple services, they often have a single Mobile Directory Number (MDN).
Existing cellular networks employ a Home Location Register (HLR) which tracks the location of mobile stations as they roam from one coverage area to another. When the network receives a message destined for a mobile station, the network sends that mobile station""s HLR a request in order to discern the current location of the mobile station. The information provided by the HLR is used to route the incoming message to a mobile station.
When an existing cellular network integrates a packet data service, a second HLR is often required for servicing the packet data messages. The existence of multiple HLRs creates routing challenges when a mobile station has a single Mobile Directory Number (MDN). The MDN is used to route a location request to the HLR associated with a particular mobile station. Standard routing procedures only allow the request to be routed to a single destination, i.e., either the existing HLR or the packet data HLR. However, the existing HLR is typically a different application than the packet data HLR and is unable to service location requests from the packet data network. Similarly, the HLR for packet data services is typically unable to service location requests from the existing cellular network. As a result, there is a need for a method and network for routing messages in a network integrating multiple communication services.
The invention relates to a method for routing messages in a telecommunications network. The method includes receiving a Signaling Connection Control Part (SCCP) message and determining the type of upper layer protocol employed in the SCCP message. The method also includes processing the SCCP message in response to the determined type of upper layer protocol. In one embodiment, the message is routed in response to the determined type of upper layer protocol.
Another embodiment of the method includes determining the type of upper layer protocol employed in the SCCP message in response to a determination that a global title address is not listed in a first routing table. The method further includes consulting a second routing table associated with the determined upper layer protocol type and searching the second routing table for the global title. The method further includes routing the message to a Home Location Register (HLR) associated with the determined upper layer protocol type in response to the global title being listed in the second routing table.